Mold for making commutators



Sept' 26, 1933. v. G. APPLE MOLD FOR MAKING COMMUTATORS Original FiledJuly 26, 1929 Patented Sept. l26, 1933 U-NITED STATES PATENT OFFICE1,928,325 MOLD FOR MAKING lcoMivrU'iAtroRs Vincent G. Apple, Dayton,Ohio; Herbert F. Apple, Edward M. Apple and Gourley Darroch executors ofsaid Vincent G. Apple, deceased originel application July 2e, 1929,serial No.

381,360. Divided and this application January 15,1932. serial No.586,883V f 4 claims. (Cl.` 18-42)` o about them.

To provide commutators of this `class suitable for high rotative speedthe core material must possess considerable mechanical as well asdielectric strength, and a certain class of phenolresin moldingcompounds meet this requirement and Vare therefore often used for thispurpose.

`But when cores made from these strong materials extend outwardlyVbetween the metal segments and form a part of the brush track of thecommutator, diiiiculty is encountered, since these materials do not makea good brush track because arcing of the brushes converts them to carbonwhich is a conductor, and thereby adjacent Y segments areV electriallyVjoined.

To overcome this objectioncommutators of this class are usuallyundercut, i. e. the core material is cut from between the segments atthe brush track, or sometimes spacers ofV sheet insulating material morenearly suited to a brush track are placed between the segments near theperiphery ofthe commutator, and the core is then molded to extendoutwardly Y between the segments until met and excluded by thesespacers. Y

It is therefore en object of this invention to produce a commutator inwhich these objections are not present, by providing apparatus and aprocedure which contemplates employing oneV kind of insulation for thecore and another kind for thespacers which separate the segments attheir outer edges adjacent the brush track, each kind being determinedby its adaptability to its particular function, and placing each whereits particular kind is needed.

Since some materials which are highly suit- 45 'able for the segmentspacers lack the necessary adhesive properties to keep them securedagainst radially outward movement during rotation of the commutator, itis a further object of the invention to provide apparatus to facilitatesecur- 4ing the spacers in place.

Other objects and meritorious features of the invention will becomeapparent, to one skilled in the art of commutator making, from aconsideration of the following description taken in conjunction with thedrawing, wherein- Figs. 1 to 6 are perspective views of different formsof segments, either of which is suitable for making a commutatorembodying my invention.

Fig. 7 is an outline of the blank from which the 60 segment shown inFig. 6 is made.

Fig. 8 is a plan view of the mold with the stock ring and the plungerremovedV to more clearly show the means for holding a plurality ofsegments, of either of the kinds shown in Figs. 1 to 65 n o 5, in spacedapart relation while a core of insulation is'molded in place. 1

Fig. 9 is a fragmentary plany view of another mold similar to that shownin Fig. 15 but modied to hold a set of segments Fig. 6.

Fig. 10 is afragmentary view of the mold Fig. 8 with segments Fig. 4 inplace between the spacing means of the mold, and a core of insulationmolded tohold the segments in spaced` relation after the structure isremoved from the mold.

Fig. 11 shows the commutator structure as it appears after removal fromthe mold in which it appear in Fig. 10. n l r Fig. l2 shows a commutatorstructure similar to that shown in Fig. l1 except that it is composed ofsegments Fig. 3 instead of segments Fig. 4. Y

Fig. 13 is a transverse section through a second mold similar to thatshown in Fig. 8 exceptthat the segments spacing means are omitted.

Fig. 14 is a vertical axial section through the second mold taken at14-14 of Fig. 13.

Similar numerals refer to similar parts throughout the several views.

Segments 25, 26 or 27 arepreferably made by providing bar stock or wireof the cross section shown and cutting it into lengths. The segments 25and 26, having no grooves or other means along their sides whichV a coremay engage to holdthem together are preferably cut diagonally atthe endsas at 31. The core of insulation may then be molded about these diagonalends to hold the segments against radially outward movement when thecommutator rotates.

The segments 28, 29 and 30 are preferably made from flat sheet stock,the segment 28 by providing a strip of sheet metal of suitable lengthand bending it downward as at 32 and the edge inward as at 33, thesegment 29 by bending a strip of sheet metal of suitable length downwardonly as at 34, and the segment 30 by cutting out a sheet metal blank ofthe outline 35, Fig. 7, having a wide portion 36 and narrower prongs 37,and curving the part 36 to the commutator radius as at 38, Fig. 6,

`-41 as is shown in Fig. 8 but with the pockets fined 44 of the mold 41.

and bending the prongs 37 downward as at 39 and inward as at 40.

The molding apparatus 41, Fig. 8, comprises a base 42 having a removablepilot 43 concentrically supported therein and a spacing ring 44 heldinconcentric relation to the pilot 43. Ring 44 has a.V

plurality of spacing tangs 45 extending inwardly from its inner wall.These tangs have T-shaped ends 46, which leaves a series of pockets 47between the tangs. A pocket 47is adapted to receive either one of thesegments 25 to 29 and one of each of these segments is shown in apocket, though of course when actually filling 4the mold with segments,preparatory to molding the core, all of one kind of segments are usedand each one and every pocket is filled.

The fragmentary view Fig. 9 shows a modified spacing ring 48 which hasshorter spacing tangs 49 with the same T-shaped heads 46. Thismodification provides pockets 50 of lesser radial depth which adaptsthis ring to hold the segments 30, with which the pockets are filled.

By consideration of Fig. 9 the advantages of,l

the T-shaped mold tangs is obvious, for, if plain tangs 49 without theT-heads 46 were used, considerable difficulty would be encountered inkeeping the segments 30 against the outer wall of the mold until acorecould be molded within them to hold them permanently. Of course theprincipal function of the T-shaped tang in the mold is to produce aTshaped slot in the core of insulation wherein another kind ofinsulation may afterward be molded and held against radially outwardmovement, and this function could of course be accomplished with moldtangs of L shape, or of otherwise'modied form,'so long as there was anenlargement of some sort at the inner end of each tang.

Fig. 10 is a fragmentary view of the same mold is removed therefrom itappears 'as at`53 Fig. 11,

the segment 28 being held by portions 52 of core 51, leaving T-slots 54between the segments. The structure 55, Fig. 12 is produced in the samemanner as the structure 53 except that segments 27 instead of segments28are used.

The mold 56, Figs. 13 and 14 has the same base 42 and pilot 43 as themold 41, Fig. 8, but a smooth bored ring 57 is substituted for thespacing ring This mold is adapted to receive the structure Fig. 12 whichis composed of segments 27 held together with the core 51 of the onekind of insulation and with the T-slots 54 between the segments, andhold it until the other kind of insulation 58 is forced into the T-slots as shown.

, COTE.

Fig. 14 shows a stock ring 59 on the ring 57 of mold 56, and a plunger60 which has been forced downward to drive the insulation 58 into theT-slots. The same base 42, pilot 43, stock ring 59 and plunger 60 areused in bothmolds 41 and 56, the only difference in the-two molds beingin the substitution of the smooth bored ring 57 for the spacing ring 44.

In operation the base 42, the pilot 43 and the spacingV ring 44 areassembled, the segment is put into each of the pockets 47 of the spacingring, the stock ring 59 is put in place, a determined quantity ofunmolded insulation of the one kind is put into the stock ring andforced downward around the segments to compose the Spacing ring 44 isthen removed and smooth ring 57 substituted, a determined quantity ofthe other kind of insulation is put into they stock ring and forced intothe T-slots by plunger 60. y

When the foregoing procedure is followed the commutator will have lacore sufficiently strong to hold the segments against radially outwardmovement at all reasonable rotative speeds and may have spacers betweenthe segments at the brush track of soft material possessing very littlestrength, and such spacers will be locked in place by the T-heads attheir inner edges.

Having described my invention, I claim,

1. Apparatus for making commutators, comprising a mold ring having aninner diameter corresponding to the outer diameter of the commutator, aseries of spacing tangs extending radially inward from the wall of saidmold ring formingV pockets within which the segments may be located tohold them circumferentially spaced, said tangs having enlarged innerends adapted to engage edges of the segments to hold them againstradially inward movement, and means to compress a core of insulationabout portions of said segments not in contact with said tangs.

2. The apparatus defined in claim 1 having a base fitted to the one sideof said mold ring and a stock ring fitted to the other and a plungerslidably fitted to said stock ring.

3. The apparatus defined in claim 1 having a base with a center plugcorresponding to the shaft opening in the commutator concentricallysupported on one side of said mold ring, a stock ring concentricallysupported on the other side of said mold ring, and a second mold ringlike and interchangeable with the first mold ring but not having thesaid spacing tangs.

4. The apparatus defined in claim 1 in which thespacing tangs having theenlarged inner ends are each in the form of a T ywith the head of the Textending inwardly.`

VINCENT Gr. APPLE.

